The present disclosure relates to an airbag apparatus that protects an occupant seated in a rear seat of a conveyance from an impact by inflating an airbag in front of the occupant when the impact is applied to the conveyance from the front of the rear seat.
A rear-seat airbag apparatus is effective for protecting an occupant seated in a rear seat from an impact when the impact is applied to a vehicle from the front due to, for example, a collision. The inflator and airbag of this airbag apparatus are both arranged in the seat back of a front seat.
German Patent Application Publication No. 10201836 discloses such a rear-seat airbag apparatus. The airbag of this airbag apparatus has an upper inflation portion and a lower inflation portion.
In the above-described airbag apparatus, when the application of an impact to the vehicle from the front is detected or when the application of an impact is predicted, the inflator supplies inflation gas to each of the upper inflation portion and the lower inflation portion.
The upper inflation portion is inflated by the inflation gas supplied from the inflator, thereby breaking the upper part of the covering, which constitutes the outer shell of the seat back. The upper inflation portion continues being inflated outside the seat back even after breaking the covering.
The lower inflation portion is inflated by the inflation gas, thereby breaking the lower part of the covering. The lower inflation portion continues being inflated outside the seat back even after breaking the covering.
An impact applied to the vehicle from the front stops the vehicle, but the occupant, who is restrained by the seatbelt device, receives a forward-moving force due to inertia. However, when the knees of the occupant are received by the lower inflation portion in the inflated state, the knees are protected from the impact and the forward movement of the occupant is restricted.
Furthermore, the upper body of the occupant, who is restricted from moving forward, receives a forward-inclining force with the knees serving as the pivot due to inertia. However, when the head of the occupant is received by the upper inflation portion in the inflated state, the head is protected from the impact and the further forward inclination of the upper body of the occupant is restricted.
In the airbag apparatus disclosed in German Patent Application Publication No. 10201836, the upper inflation portion and the lower inflation portion of the airbag are both inflated between the seat back of the front seat and the occupant in the rear seat. This requires large volumes for the upper and lower inflation portions and thus inevitably results in a larger volume of the airbag. Accordingly, a large inflator that discharges a large amount of inflation gas will be necessary.